• Latin Name: Formica exsectoides
  • Latin Family Name: Forimcidae
  • Common Name: Allegheny Mound Ant
  • Other Names: N/A

Origin:
This is a native species in eastern North America.

Biology:
This ant is one of the most common mound ant species in the eastern half of the U.S. and southern Canada. Workers create a large mound of debris on top of the soil, expanding the size over the years as the colony grows, often growing to a diameter of several feet and 3 to 4 feet high. The workers have no stinger, but they are capable of biting and then spraying a mist of acid onto that bite wound, causing a stinging sensation to the person attacked. The workers also inject this acid into plants that surround their nest mound, often killing these plants for many feet around the nest. The colony has multiple queens and development from egg to adult ant requires about 3 months. They feed on other insects (protein) and on honeydew (carbohydrate) and other plant fluids. They very rarely enter structures.

Identification:
Workers in a colony are polymorphic, ranging in length from 1/8 to ¼ inch. This is a single node ant, the head and thorax are reddish and the abdomen and legs are black. The profile to the top of the thorax is uneven, with a distinct dip about 2/3 of the way back, easily separating it from carpenter ants. A small circle of hairs is present around the tip of the abdomen.

Characteristics Important to Control:
Direct injection of contact insecticides into the mound in many places is effective, as is the application of a dust or granular contact insecticides over the top of the mound. Granular insect baits may be acceptable to the ants as well.

Photo by Peter Cristofono (top) and Larry B (middle)